Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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Which Bitcoin simulator can i use where changes in nonce size is possible?

I want to run a Bitcoin simulation in which I can have double nonce running in a loop on the block header, and I can also change the nonce sizes. which simulator can I use for this?
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Configure esplora to point to the bitcoind servers ip address

I have 2 servers running: Ubuntu 18.04 running bitcoind daemon (v0.18.1 full blockchain synchronized) Ubuntu 18.04 running esplora (the local single page website works, but it has no data from the ...
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My transaction is confirmed but 3 days unspent.. please help me [closed]

Unspent Address 1BRe6R9itBEegoauRKKLkGDPYcYa7fZpZj Value 0.00113000 BTC Pkscript OP_DUP OP_HASH160 725a3475a2d9816efa5cf255030420dede154206 OP_EQUALVERIFY OP_CHECKSIG
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Why one miner can dig out many blocks continually in one moment?

I am new to bitcoin and blockchain, I browed the website just now. There is a question confusing me, I find that one miner dig out blocks many times even in one hour. For example, this miner dig out ...
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Can i have a blockchain that is not mined or validated?

I am willing to use the blockchain technology to implement voting system. So, I am planning to create a private network consisting of only nodes through which people vote and hence, I do not want any ...
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Why Block Chain not Transactions Chain?

I believe that, for some people, the term Block is a sort of holy notion. However, there exist yet some block-free blockchains such as Libra (Sometimes referred to as Zuck Buck). Unlike previous ...
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48 views

Is it (theoretically) possible to run a small scale blockchain node on a mobile phone?

In the context of a mobile application that uses blockchain to store some textual data: is it possible to make every user (everyone that has downloaded the application) a node of this blockchain? What ...
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How to verify virgin bitcoin

I am willing to acquire bitcoin without transaction history (virgin bitcoin) at a premium. How do I tell that the bitcoins I receive do not have any prior transactions (except of the mining one)? What ...
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What are some other uses for blockchain instead of money? [closed]

What has blockchain been used for aside from money in the 10 years its been around? I know things like etherium exist, but They don't seem be going anywhere, most of its value seams to come from the ...
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Wondering about the viability of a Hardware Wallet

I want to roll my own hardware wallet using a USB stick. I have some concerns: Do I need to download the entire blockchain in order to create a new wallet? Do I need to download and store the entire ...
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Why Block Chain not Block Tree?

Why is the Blockchain intended to be a chain and not a tree? Why do orphaned blocks get trimmed off? Would you please provide a detailed answer.
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How does Bitcoin utilize cryptography and secure hash algorithm (SHA) to link records in the blockchain?

I am wondering how Bitcoin uses cryptography and secure hash algorithm such as SHA256 to link the records in the blockchain. And if possible I think it will give me a better understanding if there is ...
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Lost Transaction from Blockchain.com to Electrum

This link, https://www.blockchain.com/btc/tx/a081d03519bc0f1dcf4ac391da6f54d4d6091c458530b620f96eca5c1c5a3511, shows the transaction was delivered to the address "1Mv4fi8UdVhbfm9iLx2Bf8xhDrMv9sZSyD" ...
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Does the chain become computationally more expensive to validate over time?

Since there is only one chain per coin, doesn't that mean it becomes computationally more expensive to validate the chain the older the coin is and the longer the chain becomes?
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Race attack with transaction fees

let's say I run a simple race attack (say in a restaurant). I transfer BTC to the restaurant but seconds before (or after) I send the very same coins to myself. To make this deal more likely for ...
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Getting Started with a Hello World Node.js App making an API call to bitcoin.org

I have been reading around trying to find where/how you can attach a SHA256 or MD5 hash (i.e. a small chunk of data) to a Bitcoin transaction, which led to OP_RETURN, but I have yet to see exactly how ...
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55 views

Who can predict that a benign attacker has 51% hash rate of the system?

In the Bitcoin network, suppose that there is an attacker who has 60% hash-rate (hr) and then other users have 40% hr. Therefore, it is obcioust if other users generate any new block, attacker can ...
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How do miners determine if a wallet has sufficient funds

I have ready about 10 posts that are similar and none of them seem to answer my question so any help is appreciated. My question is how to miners technically determine if a "wallets" has the "...
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Imported address:private key [duplicate]

Please I want to ask how can I get the private key so to withdraw from my imported address and is it possible that you get to pay a certain amount of btc to get the private key..thanks in anticipation
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Understanding getchaintips in terms of chain reorganisations

I'm trying to get an understanding of the chain reorganisations my node has experienced by looking at bitcoin-cli getchaintips. The "status" of the different branches tells me the following: 1. "...
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Can we shutdown the Bitcoin blockchain?

I maybe wrong but what I think is the blockchain ledger exists as long as there are active nodes in the network. So can the Bitcoin blockchain be shutdown by shutting down power supply across the ...
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1answer
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What would be the effect on the number of leading zeros hash generation if bitcoin increase its nonce size from 32 to 60 or 100 bits?

If Bitcoin increases its nonce size from 32 bits to double or triple the size, how will it affect the speed of getting the right hash with the required number of zeros?
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Bitcoin i have been asked to send money for a private key [duplicate]

Hi i have been asked to send money for funds that are nonspendable to receive a private key to unlock it, it's from bitcoin investing. How safe is this as i'm worried i wont receive the payment. It's ...
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108 views

Blockchain Explorer says received but it's not received yet!

I sent some Bitcoin to my friends wallet since 2 days ago. It says approved and sent successfully on my end. And even on blockchain Explorer it says confirmed and received. But my friend says he hasn'...
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1answer
141 views

A Blockchain that merges mining forks and could be more power-efficient? [closed]

I'm new to blockchain technology so I'm sorry if I'm using wrong terminology. This is not a Bitcoin question, but a general blockchain question. Imagine a theoretical blockchain that uses gradual ...
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How can I know that my transaction has been confirmed on the longer chain?

This question is more on the theory of bitcoin. Let's say I receive a coin in a tx which has been confirmed with 6 blocks following the block that's been confirmed. How can I be sure that there's no ...
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Fundamentals: Addresses don't hold coins, wallets do?

In the beginning it was my understanding that: Every address has a private key Every address has a balance Every address may send and receive coins. This is simple. But now I am using more proper ...
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39 views

Is their any way to identify whether the miner is using renewable or non renewable energy for mining?

Is their any way to identify whether the miner is using renewable or non renewable energy for mining ? in decentralized way?
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what is exact meaning of some field of response of `getBlock` rpc api

I refer to this document for using getBlock rpc api. https://bitcoin.org/en/developer-reference#getblock { "hash" : "hash", (string) the block hash (same as provided) "confirmations" : n, (...
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Is it possible to share blockchain data between multiple nodes?

I'm planning to create a Raspberry Pi Cluster in order to run several bitcoin nodes. Can I share parts of the ~/.bitcoin/ folder in order to not have to store the entire hundreds of GB for each of the ...
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Wallet forensic

Someone who scammed me used this wallet to receive the BTC 12fmomENb5SSxR54Bitua71CZrc4oVQtmB he hasn't moved them from there since July 31st I'm trying to figure it if that wallet belong to any ...
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79 views

How to decode a coinbase transaction?

Below is block result of block height 200,000 { 'hash':'000000000000034a7dedef4a161fa058a2d67a173a90155f3a2fe6fc132e0ebf', 'confirmations':396774, 'strippedsize':247533, 'size':247533, ...
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how to know miner of each bitcoin block [duplicate]

Do you know from what kind of API I can get miner info per each block? I've run bitcoin mainnet, and I want to know who mines each block if possbile. I've googled and read many docs but I couldn't ...
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What is the algorithm used to calculate profitability for Bitmain mining SHA-256 [duplicate]

I want to know how I can calculate the profit of bitcoin mining using SHA-256 Algorithm. I am interested in the formula that is used by calculators. For example lets say I have 700mh/s hashrate, ...
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3answers
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How is the monetary part of bitcoin stored?

How is the monetary aspect of a bitcoin stored? I understand that the blockchain is a set of records documenting transactions. I've also seen that blockchains in general can store arbitrary ...
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2answers
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Pending transactions 0/3 [duplicate]

I sent bitcoin from my blockchain to my paxful and it says pending in my paxful history 0/3 confirm. Please what happened. And the bitcoin has left my blockchain wallet and it only showing unconfirmed ...
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58 views

How the blockchain knows that its been tampered with?

I know that the transactions stay in the block and hashed alongside few other things and that hash is stored in the next block. And I understand that if you try to tamper with one of the transactions, ...
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1answer
34 views

What is the program in Python that print information about the current block?

What is the program in Python that print information about the current block the world try to mine (I mean Version, Previous Block, Merkle Root, Time, Bits) plus how many zeros we are looking for for ...
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where can I get resource such as Blockchain technology in C++

I have found a lot of pdf files about Ethereum smart contract and JavaScript cryptocurrency. I still want to know about resources such as C++ cryptocurrency. Let me know about some good resources.
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Disable update of blocks locally with bitcoind cmdline option

I'm using blockchain2graph tool to import the Bitcoin blockchain into Neo4j. It uses JSONRPC calls to read block data. For this, I have to have the bitcoind service running. Is it possible to disable ...
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1answer
63 views

Accidentally sent Blockchain BCH to Coinbase BTC? [duplicate]

I have made a mistake by sending cash bitcoin from Blockchain to Coinbase bitcoin address ( instead of Coinbase cash bitcoin address).. i want to retrieve the fund or send it back to my blockchain so ...
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1answer
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Chain Race: How to know chain-length of competing chain?

If a fork happens, miners mine on the block they receive at first. Further, they only forward the block they received first (so the block they will use to mine)! So it can happen that 10% of the ...
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when does a transaction go through?

When exactly does the receiving party receives their payment. When the transaction is validated or when the transaction is added to a block?
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1answer
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How would a bitcoin transaction fits into a double entry accounting

A bitcoin transaction may have multiple input and multiple output. When we have a multiple input and multiple output scenario. Also, we might not be able to identify from which address the transaction ...
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Bitcoin rpc testnet balance and transaction not visible

I'm using bitcoind-0.15.0.1 version & My Wallet Address is: muweVvHKnK1bE88pUsrpSAPuWry1V1AmHZ But whenever checking balance with following command: bitcoin-cli getreceivedbyaddress '...
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Sync with community delays

(Hello), I'm having some issues with Bitcoin Core, it is sync with community and the ETA suddently starts to increase. Now it shows 5 weeks, but it increases randomly. I think my internet connection ...
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Why is 550 (MiB) chosen for minimum storage size for prune mode?

As you know Bitcoind can run in pruned mode, thus not advertising blocks to other nodes. Even though it has some drawbacks, saving you storage space isn't a benefit you can ignore. My question is ...
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Witness data storage localisation in the blockchain

Since segregated witness is in place inside Bitcoin blockchain, my understanding is that witness data are no longer stored inside the blocks, so if blocks are linked to each other where theirs ...
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Regarding 51% attacks in blockchain [duplicate]

Can anyone tell me, What is 51% attack in blockchain how this attack is prevented